Peggie, what do you know about a Mansfield, 1983 last year for them before sell out. It will not cycle or treat, and we cannot find the fuse. I know reverse polarity, no power will cause this or blown fuse. I cannot find the fuse. I thought it was supposed to be at the treatment tank, but it is not.

The only fuse in it is in the chemical injection pump. However, if that one were blown, it wouldn't affect whether the unit runs or not, only whether it gets any chemical. My guess is, one or more of the 3 relays in the control module has failed....relays are available from Radio Shack. If that's not it, the control module has had it, which means the system is toast, 'cuz no parts have been available for it for about 10 years.

As you already know, but for the benefit of others...Mansfield spun off their marine products division to SeaLand in 1984....the TDX didn't change much for several years afterward, then it was redesigned--all new versions of the same parts, actually, they were just designed to make sure the old ones no longer fit--and renamed the SanX...about 5 years after that, SeaLand ceased to support either the Mansfield OR SeaLand "TDX" version with parts or tech support...and discontinued the SanX altogether earlier this year. Parts, and of course the chemical TDX will remain available for a few years longer, but for all intents, it's now an obsolete system.